This invention relates to electrically powered devices used as lawn and garden decorations, for holidays and other purposes.
Holiday decorations containing lamps and moving parts have been popular for both indoor and outdoor use for many years. Lighting devices include many types of miniature light sets with flashing lamps, and Rudolph the Reindeer's flashing red nose leading Santa's sleigh. Moving devices include such favorites as Santa Claus waving to onlookers, and toy trains and Ferris wheels in motion.
Non-holiday uses of similar devices include advertising signs with flashing lights, and miniature waterwheels.
These prior art devices usually receive power from an AC outlet, which in the U.S. is a 120 volt AC power source. Although there have been safety improvements over the years, the basic dangers of this potentially lethal voltage level still exist.
By design, the decorations attract children. Children want to touch the devices and could contact the power source accidentally. Pets, or even wildlife, can encounter the same fate.
The high voltage is a hazard when the decorations or cords are exposed to moisture. Rain or snow could provide a path for high voltage to reach what would normally be a non-energized area of the decoration. Because of this danger, the types of decorations that can be implemented outdoors are limited. Some must be restricted to indoor use only.
Each light set or device must be plugged into the AC power separately. This yields a large tangle of wires and extension cords if the user has several such devices in operation. The exposed cords further enhance the danger to children and pets. No matter how safe the decorations themselves are, the cords always present a hazard.
Holiday decorations frequently allow the power plugs to be stacked, so that many can share an AC outlet. The stack of plugs has a large number of points where children, animals, or moisture can contact the high voltage. The stack of plugs tends to come apart under its own weight, exposing energized conductors.
Users frequently purchase a separate timer to provide automatic on/off control of their decorations. Often no attention is paid to obtaining an outdoor rated timer for an outdoor installation. And many timers have only one socket, requiring extension cords and stacked plugs to deliver the power to many devices at once. The timer powers all attached equipment on or off simultaneously, with no ability to select which equipment is on and which is off.
Battery-powered decorations are available to overcome the safety hazards of the high AC voltage. However, batteries cannot power a medium or large-sized installation economically. Hundreds of watts of power may be necessary to operate several light sets and associated motorized devices. And batteries contain heavy metals and other substances harmful to the environment when they are disposed of.
U.S. Pat. No. 3,944,878 to Gerontakis (1976) describes a method of energizing multiple lights in a number of predetermined sequences. However, this requires multiple lighting circuits, and therefore cannot be implemented on a two-wire cable.
U.S. Pat. No. 5,784,815 to Hermanson (1998) shows a decoration featuring motorized movement, lighting, and an electrically insulating shield over some components. However, as with other prior art devices, it is powered by standard AC power (120 volts, U.S.).
U.S. Pat. No. 5,322,717 to Killian (1994) shows an outdoor ornament with motor, sound generation, and trigger devices such as a clock, photocell, or microphone. However this device is powered by wires entering its base, not by a two-conductor low voltage cable, and lacks an insulation-piercing connector.
U.S. Pat. No. 5,785,413 to Tillinghast et al. (1998) describes a vehicle light fixture which can be individually addressed for on/off control. However, power and commands are received on separate buses. Therefore a minimum of four wires are necessary.
U.S. Pat. No. 4,734,625 to Geanous et al. (1988) allows control of multiple low-voltage lamps from a remote point. However, each lamp requires its own circuit, again making it impossible to connect the whole system to a single two-wire bus.
Prior art low voltage lighting systems, including the widely used 12 volt AC systems manufactured by Intermatic Inc. (Spring Grove, Ill.), Noma Inc. (Scarborough, Canada), and Toro Co. (Bloomington, Minn.), allow on-off control of an entire string of lights through a switch located in the low voltage power supply. However, these systems do not provide on/off or flashing control of individual light fixtures. A high frequency system described in U.S. Pat. No. 4,906,901 to Carroll (1990) suffers the same limitations.
U.S. Pat. No. 5,247,753 to Yang (1993) allows attachment of a motorized decoration to a miniature light set used on a Christmas tree. This arrangement uses standard AC power and series-connected devices. The advantages of a parallel-connected bus, low voltage, and insulation-piercing connectors are thus lost.
U.S. Design Pat. No. D379,777 to Segan et al. (1997) illustrates a decoration containing multiple motorized components connected together by fixed length wires. There is no ability to connect an arbitrary number of decorations at varying distances from each other. Although not shown in the drawings, in practice this type of decoration plugs into a standard AC outlet and is intended for indoor use only.